Oxide thin film transistor (Oxide TFT) is a development direction of the large-scale, active matrix organic light-emitting diode (AMOLED) display/liquid crystal display (LCD), so it is widely adopted for an existing gate on array (GOA).
As one feature of the Oxide TFT, it is capable of being depleted, i.e., a threshold voltage of the Oxide TFT may be negative. As a result, there is always leakage current for the existing GOA.
For an existing typical GOA circuit as shown in FIG. 1, at a precharge stage, there is relatively serious electric leakage at T14, so the charging effect of a gate electrode of T11 becomes worse. At a pull-up stage, a minimum level of gate electrodes of T12, T13 and T14 is merely VGL while the level of source electrodes of T12, T13 and T14 is VGL too, so a minimum gate-to-source voltage VGS of T12, T13 and T14 is 0. The threshold voltage of the Oxide TFT is less than 0, so T12, T13 and T14 still are in a lightly-on state, and there is relatively large leakage current. As a result, both the gate electrode and the source electrode of T11 have an electric leakage toward VGL, and the normal pull-up and output of the GOA circuit will be affected. At a pull-down stage, T12 and T14 cannot be switched off normally, so that the pull-down waveform is distorted and the pull-down effect is affected, thereby the reliability and power consumption of the GOA circuit is affected.